• Energy Research

AbstractEnergy conservation in brick production is crucial to achieving net-zero carbon emissions from the building sector, especially in countries with major expansions in the built environment. However, widely disparate energy consumption estimates impede benchmarking its importance relative to the steel and cement industries. Here we modelled Indian brick production and its regional energy consumption by combining a nationwide questionnaire survey on feedstock, process variables and practices with remote sensing data on kiln enumeration. We found a large underreporting in current official estimates of energy consumption, with actual energy consumption comparable to that in the steel and cement industries in the country. With a total estimated production of 233 ± 15 billion bricks per year, the brick industry consumes 990 ± 125 PJ yr−1 of energy, 35 ± 6 Mt yr−1 coal and 25 ± 6 Mt yr−1 biomass. The main drivers of energy consumption for brick production are the kiln technology, the production capacity and the fuel mix used. The results suggest that improving operating practices would be a first step in making brick production more energy efficient.

Forest fires are one of the most common natural and anthropogenic events that have long-term impacts on the environment. In this study, we analyzed 17 years of data on forest fires in Chhattisgarh, India, using active fire and burned area data from the Moderate Resolution Imaging Spectroradiometer. Chhattisgarh was selected as the study area due to its high incidences of forest fires, significant forest cover, and scarce studies on forest fires. Our findings showed that the number of forest fires in the region increased over time, from 1487 forest fires in 2005 to 3074 forest fires in 2021, with the highest number of fires occurring in 2017 and 2009. Most of the fires occurred in deciduous broadleaf forests and savannas, following a consistent seasonal pattern, with the highest percentage of fires (88.88%) occurring in March, April, and May. The fire hotspot was located in the southwest region, dominated by deciduous broadleaf forests which are particularly prone to fires. These results emphasize the significance of effective fire management strategies that consider the seasonal and annual variability of forest fires, particularly in high-risk areas. Immediate attention to controlling forest fires is also critical to minimize its impact on the environment and local communities.

India is a major emitter of mercury to the environment, mainly due to emissions from coal-fired power plants. Consumption of fish and rice, two important pathways for human exposure to mercury, is particularly high in South India. Here, we report concentrations of total mercury in hair (THghair) in 668 participants from South India. Three cities were covered: (i) a city on the east coast with four active coal-fired thermal power plants (Nellore), (ii) a city on the west coast with no major mercury source (Vasco da Gama), and (iii) a metropolitan city in the interior with no major mercury source (Hyderabad). Geometric mean of THghair of the entire study population is 0.14 µg/g (95% confidence interval, CI: 0.13-0.15 µg/g). Significant predictor variables are age, fish consumption, and occupations such as dental studies, subsistence fishing, and artisanal goldsmithing (which is different from artisanal scale gold mining). Our results support the hypothesis that people living in a city with active coal-fired power plants may have higher THghair than those in cities with no major mercury source.

Abstract Understanding the climate impact of residential emissions starts with determining the fuel consumption of various household activities. While cooking emissions have been widely studied, non-cooking energy-consumption activities in the residential sector such as heating and lighting, have been overlooked owing to the unavailability of data at national levels. The present study uses data from the Carbonaceous Aerosol Emissions, Source Apportionment and Climate Impacts (COALESCE) project, which consists of residential surveys over 6000 households across 49 districts of India, to understand the energy consumed by non-cooking residential activities. Regression models are developed to estimate information in non-surveyed districts using demographic, housing, and meteorological data as predictors. Energy demand is further quantified and distributed nationally at a 4 × 4 km resolution. Results show that the annual energy consumption from non-cooking activities is 1106 [201] PJ, which is equal to one-fourth of the cooking energy demand. Freely available biomass is widely used to heat water on traditional stoves, even in the warmer regions of western and southern India across all seasons. Space heating (51%) and water heating (42%) dominate non-cooking energy consumption. In comparison, nighttime heating for security personnel (5%), partly-residential personal heating by guards, dominant in urban centers and kerosene lighting (2%) utilize minimal energy. Biomass fuels account for over 90% of the non-cooking consumption, while charcoal and kerosene make up the rest. Half of the energy consumption occurs during winter months (DJF), while 10% of the consumption occurs during monsoon, when kerosene lighting is the highest. Firewood is the most heavily used fuel source in western India, charcoal in the northern hilly regions, agricultural residues and dung cake in the Indo-Gangetic plains, and kerosene in eastern India. The study shows that ∼20% of residential energy consumption is on account of biomass-based heating and kerosene lighting activities.

Coal combustion is the largest source of power in India at the moment. This combustion also emits trace amounts of hazardous substances such as mercury. Mercury is a global pollutant with the potential for long-range transport and ability to persist in the environment, bioaccumulate and cause toxicity. Controlling emissions of mercury from coal-fired power plants (CFPPs) is recognized by the Minamata Convention on Mercury as an important step in curbing the harmful effects of mercury to the environment and humans. India has been identified as one of the top emitters of mercury to the atmosphere, and coal combustion contributes to more than half of these emissions. Here, we discuss the current state of regulations on mercury emissions from CFPPs in India, the current information on mercury from CFPP stacks, and the possible way forward. Present data suggest that mercury specific emission control technologies are not required to comply with the regulatory requirements. As such, any reduction in mercury emissions will rely on co-benefits obtained from technologies to control emissions of other pollutants such as flue gas desulphurization, or methods to increase the efficiencies of CFPP such as coal washing. Additional reductions may be made from a business-as-usual scenario if the energy mix of India changes to renewable non-fossil fuel-based energy at an accelerated pace. Quantitative studies assessing the role of such climate change policies on mercury emissions reduction are recommended.

More than three billion people rely on seafood for nutrition. However, fish are the predominant source of human exposure to methylmercury (MeHg), a potent neurotoxic substance. In the United States, 82% of population-wide exposure to MeHg is from the consumption of marine seafood and almost 40% is from fresh and canned tuna alone1. Around 80% of the inorganic mercury (Hg) that is emitted to the atmosphere from natural and human sources is deposited in the ocean2, where some is converted by microorganisms to MeHg. In predatory fish, environmental MeHg concentrations are amplified by a million times or more. Human exposure to MeHg has been associated with long-term neurocognitive deficits in children that persist into adulthood, with global costs to society that exceed US$20 billion3. The first global treaty on reductions in anthropogenic Hg emissions (the Minamata Convention on Mercury) entered into force in 2017. However, effects of ongoing changes in marine ecosystems on bioaccumulation of MeHg in marine predators that are frequently consumed by humans (for example, tuna, cod and swordfish) have not been considered when setting global policy targets. Here we use more than 30 years of data and ecosystem modelling to show that MeHg concentrations in Atlantic cod (Gadus morhua) increased by up to 23% between the 1970s and 2000s as a result of dietary shifts initiated by overfishing. Our model also predicts an estimated 56% increase in tissue MeHg concentrations in Atlantic bluefin tuna (Thunnus thynnus) due to increases in seawater temperature between a low point in 1969 and recent peak levels-which is consistent with 2017 observations. This estimated increase in tissue MeHg exceeds the modelled 22% reduction that was achieved in the late 1990s and 2000s as a result of decreased seawater MeHg concentrations. The recently reported plateau in global anthropogenic Hg emissions4 suggests that ocean warming and fisheries management programmes will be major drivers of future MeHg concentrations in marine predators.

Cropland residue burning is one of the major causes of the emission of greenhouse gases and pollutants into the atmosphere, and is a major global environmental problem. This study analyzes the spatiotemporal changes in greenhouse gas emissions from cropland residue burning in Chhattisgarh, India. The Moderate Resolution Imaging Spectroradiometer (MODIS) active fire data was analyzed over a 21-year (2001–2021) period, and associated greenhouse gas emissions were estimated. A total of 64,370 fire points were recorded for all land cover types. The number of cropland fires increased from 49 to 1368 between 2001 and 2021, with a burning peak observed between December and March. Fires in cropland areas contributed to 32.4% (19,878) of the total fire counts in the last 21 years. The total estimated emissions of greenhouse gases between 2001 and 2021 ranged from 421.5 to 37,233 Gg, with an annual rate of emission of 8972 Gg from wheat residue burning, and from 435.45 to 64,108.1 Gg, with an annual emission of 15,448.16 Gg from rice residue burning. The Chhattisgarh plain region was the cropland fire hotspot of the state. The present study indicates increased cropland residue-burning activity in Chhattisgarh. Therefore, there is an immediate need to develop sustainable alternative methods for agricultural residue management and eco-friendly methods for the disposal of crop residues.